duanbeng8872
2016-02-20 08:23
浏览 255
已采纳

如何在没有任何SMTP服务器的情况下使用golang发送电子邮件

I want to send bulk mail from a server application written in golang. I just don't want to use any third-party smtp server to avoid usage quota limitations.

How can I send email without a smtp server? Is smtp package in standard library can help me? All example I see using the smtp package requires a third-party smtp server to send email.

图片转代码服务由CSDN问答提供 功能建议

我想从用golang编写的服务器应用程序发送批量邮件。 我只是不想使用任何第三方smtp服务器来避免使用配额限制。

在没有smtp服务器的情况下如何发送电子邮件? 标准库中的smtp软件包可以帮助我吗? 我看到的所有使用smtp软件包的示例都需要第三方smtp服务器才能发送电子邮件。

  • 写回答
  • 好问题 提建议
  • 关注问题
  • 收藏
  • 邀请回答

2条回答 默认 最新

  • doudouji2016 2016-02-20 10:20
    已采纳

    There is only one way to send an e-mail message without directly communicating with an SMTP server: delegate this action to some other program.

    What program to pick, is an open and wide question in itself because there are lots of programs which are able to send mails.

    On the other hand, if we talk about POSIX systems such as GNU/Linux- or *BSD-based operating systems, they usually come with the binary /usr/sbin/sendmail or, sometimes, /usr/bin/sendmail which is either provided by the real Sendmail package or by another MTA which exist in abundance—ranging from full-blown MTAs such as Postfix or Exim to narrow-scoped "null-clients" such as ssmtp or nullmailer.

    This program is usually called with the -t command-line option which makes it read the addresses of the message recipients from the To headers of the mail message itself.

    Basically calling /usr/sbin/sendmail -t and piping the full message's text to its standard input is what PHP's mail() function does, FWIW.

    While you can do this call directly using the os/exec, net/mail and net/textproto standard packages, the popular gomail package provides a simpler way to do that: its Message type provides the WriteTo() method which is able to write to a running Sendmail instance, like this (copied from a real program of mine):

    const sendmail = "/usr/sbin/sendmail"
    
    func submitMail(m *gomail.Message) (err error) {
        cmd := exec.Command(sendmail, "-t")
        cmd.Stdout = os.Stdout
        cmd.Stderr = os.Stderr
    
        pw, err := cmd.StdinPipe()
        if err != nil {
            return
        }
    
        err = cmd.Start()
        if err != nil {
            return
        }
    
        var errs [3]error
        _, errs[0] = m.WriteTo(pw)
        errs[1] = pw.Close()
        errs[2] = cmd.Wait()
        for _, err = range errs {
            if err != nil {
                return
            }
        }
        return
    }
    

    Actually, relying on MTA to deliver your mails has an advantage is that full-blown MTAs support mail queuing: that is, if an MTA is unable to send your message right away (say, due to a network outage etc) so it will save the message in a special directory and will then periodically try delivering it again and again until that succeeds or a (usually huge, like 4-5 days) timeout expires.

    已采纳该答案
    评论
    解决 无用
    打赏 举报
  • duanmeng1862 2016-02-20 10:07

    Your question looks like - can I show webpages to users without a web-server? Yes you can if you are able to write your own web-server.

    Can you write SMTP server on Go? Yes. Google shows few solutions for "golang smtp server" query. So I'm pretty sure you can integrate SMTP server functional into your application.

    But as commenters said - most part of your messages (if not all) would go directly to spam folder on most part of services.

    评论
    解决 无用
    打赏 举报

相关推荐 更多相似问题